Hey guys I just got my 85 lt250r a couple months ago. It has a ton of compression, starts and runs crisp, but when I get on it it doesn’t seem to have the power and I am used to at all. Has a full FMF exhaust and open air filter, which is why I won’t ride it in dirt yet.I just found an airbox inline. I was thinking maybe not jetted right, or carb air/fuel maybe. I run 40:1. Thank you. Never had this problem with a 2 stroke and I have had many.
So if you'd had many why can't you figure this problem out?...🤣🤣🤣 just kidding...😃 so here are some suggestions: ALWAYS start easy and eliminate the easy stuff so, 4 initial things to look for:
1) Sparkplug...ensure it's all in one piece and clean, sometimes a dirty plug can hinder the spark at Wide Open Throtle (WOT)
2) Intake...ensure there no rags, paper nor any obstructions within your intake system, air filter is clean so as to let it breathe well at WOT...
3) Main Jet...make sure it isn't plugged...if the bike has sat for a long time before you got it and there's a lose goober(s) in the bowl plugging the damned thing...
4) Needle...make sure you have one...not having one can cause it to have tremendously rich mixtures at WOT
Obviously, you've checked there's plenty of fuel, but if the fuel level is just at the border line, with an on/off petcock notmally is not an issue, but it it has "Reserve" sometimes the Reserve part of the petcock since it's lower, it gets polluted and it blocks fuel from feeding the motor at WOT, but it feeds enough for the low end. Also, and if there's a filter, remove it and try it without it and see what happens. If there's a Power Valve check it for correct function and cleanliness.
If everything I've mentioned checks out, then you might want to start looking at ignition performance at high demand ie:WOT...but for now, just stick to the easy basics...